As shown in Patent Literature 1, a conventional touch sensor system configured to detect how capacitance values are distributed has been trying to carry out recognition of a finger and part of a hand which are in contact with a touch panel by means of signal processing. For example, assume that a hand holding a stylus is in contact with a touch panel. A signal based on how the touch panel is touched significantly changes over time according to action of moving the stylus etc.
(a) to (d) of FIG. 5 are views for describing touch signals observed when a hand is placed on a touch panel. As shown in (a) of FIG. 5, a region where the hand is placed on the touch panel is small at first, i.e., the region is a region 16a. Then, as shown in (b) of FIG. 5, the region where the hand is placed on the touch panel expands over time to a region 16b. Next, as shown in (c) of FIG. 5, the region where the hand is placed on the touch panel further expands over time, and a tip of a stylus held in the hand makes contact with the touch panel. This causes a stylus input region 18 to appear. After that, as shown in (d) of FIG. 5, the region where the hand is in contact with the touch panel changes from the region 16c to a region 16d, and a region 17 where a finger is in contact with the touch panel appears.